package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collections;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    //全局ID
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //使用悲观锁---同步方法
    @Resource
    private RedissonClient redissonClient;
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //获取用户
//        Long userId = UserHolder.getUser().getId();
//        long orderId = redisIdWorker.nextId("order");
//        // 1.执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(), userId.toString(), String.valueOf(orderId)
//        );
//        int r = result.intValue();
//        // 2.判断结果是否为0
//        if (r != 0) {
//            // 2.1.不为0 ，代表没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        //TODO 保存阻塞队列
//        // 3.返回订单id
//        return Result.ok(orderId);
//    }

//        使用悲观锁---同步方法
@Override
public Result seckillVoucher(Long voucherId) {
    // 1.查询优惠券
    SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
    // 2.判断秒杀是否开始
    if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
        // 尚未开始
        return Result.fail("秒杀尚未开始！");
    }
    // 3.判断秒杀是否已经结束
    if (voucher.getEndTime().isBefore(LocalDateTime. now())) {
        // 尚未开始
        return Result.fail("秒杀已经结束！");
    }
    // 4.判断库存是否充足
    if (voucher.getStock() < 1) {
        // 库存不足
        return Result.fail("库存不足！");
    }
    Long userId = UserHolder.getUser().getId();
    //创建锁对象(新增代码)
    SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
    //获取锁对象
    boolean isLock = lock.tryLock(1200);
    //加锁失败
    if (!isLock) {
        return Result.fail("不允许重复下单");
    }
    try {
        //获取代理对象(事务)
        IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
        return proxy.createVoucherOrder(voucherId);
    } finally {
        //释放锁
        lock.unlock();
    }
}

        @Transactional
        public Result createVoucherOrder(Long voucherId) {
            Long userId = UserHolder.getUser().getId();

            // 5.1.查询订单
            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
            // 5.2.判断是否存在
            if (count > 0) {
                // 用户已经购买过了
                return Result.fail("用户已经购买过一次！");
            }

            // 6.扣减库存
            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1") // set stock = stock - 1
                    .eq("voucher_id", voucherId).gt("stock", 0) // where id = ? and stock > 0
                    .update();
            if (!success) {
                // 扣减失败
                return Result.fail("库存不足！");
            }

            // 7.创建订单
            VoucherOrder voucherOrder = new VoucherOrder();
            // 7.1.订单id
            long orderId = redisIdWorker.nextId("order");
            voucherOrder.setId(orderId);
            // 7.2.用户id
            voucherOrder.setUserId(userId);
            // 7.3.代金券id
            voucherOrder.setVoucherId(voucherId);
            save(voucherOrder);

            // 7.返回订单id
            return Result.ok(orderId);

        }
}
